I've seen quite a few people report "power calibration error" when using the beta firmwares...
I have not seen this myself at all.
However, I do not use Nero. I stick with RecordNow 4.6
Unfortunately, I am currently 'out of stock' of CMC F01 so I can not test these myself... CMC batches will sometimes vary in quality
OC-Freak, were you using Nero for your CMC F01 8X burn posted in the Herrie beta firmware thread?